The Pirate Party UK will join an international day of action against controversial copyright agreement Acta on Saturday with protests planned for London, Glasgow and Nottingham.

Acta, or the Anti-Counterfeiting Trade Agreement, sparked opposition from internet users who fear it will lead to online censorship.

Pirate Party UK leader Loz Kaye said: "We saw what the combination of protest and political pressure achieved with the dropping of Sopa [the Stop Online Piracy Act].

"But the threats to digital rights and civil liberties aren't over. It's vital that we send a clear message that the people of Europe don't want Acta."

A far-reaching agreement that aims to harmonise international standards in areas that often fall victim to intellectual property theft, such as music, film and fashion, Acta has been signed off by the UK and more than 20 other EU member states.

Opponents fear that it will also lead authorities to block content on the internet.

It has already been signed by the US and is to be debated by the European parliament in June.

Acta prompted widespread protests in Poland and led to attacks on Polish government websites by hacking collective Anonymous.

Finlay Archibald, spokesman for Pirate Party Scotland, added: "I hope to see many of my fellow citizens out next Saturday to demand that free speech and privacy online be eroded no further, and to let the political establishment know that they cannot simply bypass democracy like this without people noticing."